Shear and Flexural Stiffnesses of Reinforced Concrete Shear Walls Subjected to Cyclic Loading

摘要

Seismic analyses of concrete structures under maximum-considered earthquakes require the use of reducedstiffness accounting for cracks and degraded materials. Structural walls, different to other flexural dominated components,are sensitive to both shear and flexural stiffness degradations. Adoption of the gross shear stiffness for walls in seismicanalysis prevails particularly for the design codes in the US. Yet available experimental results indicate that this couldoverstate the shear stiffness by more than double, which would hamper the actual predictions of building periods andshear load distributions among columns and walls. In addition, the deformation capacity could be drastically understatedif the stipulated constant ductility capacity is adopted. This paper reviews the available simplified shear and flexural models,which stem from classical mechanics, empirical formulations and/or parametric studies, suitable for structural walls atthe state-of-the-art. Reviews on the recommended flexural and shear stiffnesses by prominent design codes such asACI318-11, Eurocode 8 and CSA are included. A database comprised of walls subjected to reverse-cyclic loads is formedto evaluate the performance of each model. It is found that there exist classical models that could outweigh overconservativecodified values with comparable simplicity for practical uses.